I found a discussion in a forum that led nowhere. I "solve" the problem by changing my settings by choosing "prefer enigmail(openpgp)" vs "prefer s/mime".
On 3/2/19 11:27 PM, riveravaldez wrote: >> I want to report it as a bug. How should i report it as a thunderbird or >> enigmail bug? > > Have you checked upstream on Thunderbird [1,2,3] and Enigmail [4,5] > sites/communities? > > [1] https://www.thunderbird.net/en-US/ > [2] https://developer.mozilla.org/en-US/docs/Mozilla/Thunderbird > [3] https://support.mozilla.org/en-US/products/thunderbird > [4] https://enigmail.net/index.php/en/ > [5] https://enigmail.net/index.php/en/support/reporting-defects >